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1. ⇒ (MHT CET 2023 12th May Morning Shift )

What are the number of octahedral and tetrahedral voids in 0.3 mole substance respectively if it forms hcp structure?

A. $1.8066 \times 10^{23}$ and $3.6132 \times 10^{23}$

B. $3.6132 \times 10^{23}$ and $1.8066 \times 10^{23}$

C. $6.022 \times 10^{23}$ and $12.044 \times 10^{23}$

D. $12.044 \times 10^{23}$ and $6.022 \times 10^{23}$

Correct Option is (A)

Number of atoms in $0.3 mol$

$\begin{aligned} = 0.3 \times N_{A} \\ = 0.3 \times 6.022 \times 10^{23} \\ = 1.8066 \times 10^{23} \end{aligned}$

i. For hcp structure, Number of octahedral voids

$=$ Number of atoms

$= 1.8066 \times 10^{23}$

ii. For hcp structure, Number of tetrahedral voids

$= 2 \times$ Number of atoms

$\begin{aligned} = 2 \times 1.8066 \times 10^{23} \\ = 3.6132 \times 10^{23} \end{aligned}$

2. ⇒ (MHT CET 2021 20th September Evening Shift )

How many total voids are present in 1 mole of compound that forms hcp structure?

A. $1.806 \times 10^{24}$

B. $1.204 \times 10^{24}$

C. $3.011 \times 10^{23}$

D. $6.022 \times 10^{23}$

Correct Option is (A)

Total no. of voids

= $3 \times 6.022 \times 10^{23}$

= $1.806 \times 10^{24}$

⇒Solid State